In a skillet, heat oil over medium-high. Soften Tortillas in the hot oil for 20 seconds per side. Drain on paper towels, cool. In a large saucepan, melt butter over medium heat. Blend in flour. Whisk in the broth: cook and stir until thickened. Remove from the heat; stir in sour cream and taco sauce. Keep warm but do not boil. Divide the chicken, 1 1/2 cups Monterey Jack cheese and all but 2 Tbsp. of the onions over the tortillas.

Arrange asparagus over filling, with the tips extending beyond the tortillas. Top each with 2 Tbsp. sauce. Roll up and place with seam side down in a 13x9x2 baking pan. Top with remaining sauce and the Parmesan cheese.

Bake at 400° for 25 minutes or until bubbly. Sprinkle with remaining Monterey Jack cheese; return to the oven just until melted. Garnish with olives and reserved onions.